1) If you want something that is super-easy to do and super-informative,
make yourself a fluttering card. A piece of card stock 1" wide by 11"
long works fine. Not corrugated, just thin and flat.
I recommend this verrrry strongly. When I get invited to give the
colloquium somewhere, I take about ten such things with me, so I
can thrown them without stopping to pick them up (until later).
This is part of a pedagogical "building block" strategy. This
explains /part/ of how a wing works. To say the same thing the
other way, if you don't understand how the tumbling card produces
lift, you have zero chance of understanding how a wing works.
Also no chance of understanding how a breaking pitch works.
A lot of people have deep-seated misconceptions about how a
wing works. This demo, if you believe what it is telling you,
washes away a tremendous number of misconceptions.
2) Stay away from wings that rotate around any other axis --
including helicopters, boomerangs, and propellers -- until
you have a *firm* understanding of how a regular non-rotating
wing works. Fussing with rotating wings is not just learning
to swim by jumping into the deep end; it is jumping into the
maelstrom.
3) *IF* you are in a position where Bernoulli's principle can
be applied, then applying it is like sinking a 3-inch putt.
On the other hand, you will find that (with rare exceptions)
it takes a lot of skill and effort to get into that position.
I mention this because a lot of the so-called "Bernoulli demos"
involve about a dozen things, each of which is harder to grasp
than Bernoulli. People get the wrong answer for reasons having
nothing to do with Bernoulli, and then go on their merry way.
In particular, if you think you can guess what the flow field
looks like in the vicinity of a wing, you are almost certainly
fooling yourself. True story: Once upon a time I wrote some
computer fluid dynamics and visualization software. What it
showed me was so different from my expectations that I spent
a long, long time looking for bugs in the code. But there
weren't any. The error was in my expectations.
Even big-name aerodynamics professors get fooled. I know a
guy who put a diagram on the cover of the book. Years later
it was pointed out that the diagram does not satisfy the
equation of motion. He argued that it did, but lost the
argument.
I'm not saying that people should never guess. I am however
saying that you have to check that your guesses are correct.
Most of the right answers have been known for over 100 years,
since even before airplanes existed ... but the right answers
are mostly to be found in the professional engineering literature,
aimed at people who are comfortable with calculus of a complex
variable, including conformal transformations. Boiling that
down so it can be understood -- by ordinary mortal physics
teachers, flight instructors, and their students -- is not
easy, but it can be done. https://www.av8n.com/how/htm/airfoils.html
4) If you think an airplane wing has to be curved on top and
flat on the bottom, you are seriously fooling yourself. A
barn door will fly just fine. A generic $1.00 balsa glider
has completely flat "barn door" wings. http://www.quill.com/s-s-games-activities/cbs/50186705.html
More than a few real-world airplanes have airfoils that are
completely symmetric top-to-bottom, with zero camber.
5) A automobile makes a fair substitute for a wind tunnel.
This allows you to get the feel (literally) for barn doors
and other airfoils at various angles of attack.
You need a driver who can be trusted to pay attention to
the driving and not to the experiment, while somebody else
takes care of the experiments.